Sauna heater technology has advanced far beyond the old-fashioned hot rock era. The health benefits of saunas have been recognized for centuries, beginning with ancient Roman baths, to sweat lodges, and other primitive systems that evolved into the well-known traditional hot rock saunas and have culminated in the far infrared (“FIR”) saunas one finds in the market today. All are based on the idea that heating the body and producing perspiration cleanses the cells and pores by removing unwanted substances, such as toxins and acids in the process. Typically, a heat source using wood, electric, or gas is used to produce the heat in a sauna. The old-fashioned hot rock saunas require extreme, and often, unsafe heat, which warms the room, the walls, and the entire sauna environment prior to transferring any significant heat to the individual seated within the sauna. In addition, once constructed in place, traditional electric heating elements in hot rock saunas have considerable power requirements and are often nearly impossible to move to a different location.
Thus, in recent years, far infrared technology has been used to replace the traditional hot rock saunas. Infrared (“IR”) energy, or radiant heat, is commonly regarded as that electromagnetic energy with a wavelength between 0.75-1,000 microns (“μm”) on the electromagnetic spectrum, bordering on the visible light spectrum. Far infrared light is usually regarded as being found in the range of wavelengths from 5.6-1000 μm, the longer wavelengths of the IR spectrum while “near” IR and “mid” IR fall in the realm of wavelengths shorter than 5.6 μm, and “nearer” the visible light spectrum with respect to frequency and wavelength. The terms “near,” “mid,” and “far” as applied to IR energy, all refer to their proximity to the visible light spectrum. All infrared light falls outside the visible spectrum, thus is not visible to the human eye. IR energy, or IR radiation as it is often known, including FIR, is perceptible as heat, like the warming rays of the sun. Infrared saunas use this infrared radiation, to heat the body directly, rather than heating the air, and the entire environment around the body, such as a hot rock sauna does.
IR energy, and more specifically, far infrared rays, unlike UV radiation, x-rays, or atomic radiation, are safe and often beneficial. When FIR energy hits the skin it transfers heat energy, which penetrates more than an inch and a half into the body to heal and stimulate tissues, making FIR an effective therapeutic tool for arthritis and tissue injuries among other ailments and conditions. In addition, this heating causes the individual to sweat, thus achieving health benefits similar to those from a traditional rock sauna heating techniques.
Studies indicate that the use of a far infrared sauna using the correct frequency of infrared rays triggers a process called “resonant absorption” wherein toxins are removed from the cells in our bodies at a higher rate than achieved by high ambient temperatures alone. When comparing far infrared saunas to traditional hot rock saunas, FIR has several other advantages as well. One of the most important differences between traditional hot rock saunas and FIR saunas is the infrared energy enables the IR heating elements to function at a lower surface temperature. Traditional hot rock saunas typically operate at temperatures ranging from 180° F. to 190° F. This high heat can be uncomfortable or even dangerous for some people, especially those with cardiovascular or respiratory problems and can limit the time one can spend in the sauna. This, in turn, limits the amount of sweat that can be produced due to an individual's tolerance of the environment, reducing the amount of therapy obtainable. The heavy, thick air can be difficult to breathe and evaporation can dry out membranes in the nose and eyes, furthering discomfort.
A FIR sauna, on the other hand, typically functions between 100° F. and 140° F., wherein it is estimated that less than 20 percent of the infrared energy generated by the heater goes into the air. Thus, not only does the body receive the other 80 percent of the heat directly, including all of its benefits, many individuals find that the air is more breathable, and apart from the FIR heating elements, there are no hot surfaces.
A further benefit of FIR saunas is that an infrared sauna heater uses considerably less electricity than traditional hot rock saunas that use electricity as the power source. The infrared sauna is usually ready to use within 15 to 30 minutes, whereas a traditional rock sauna (depending on their size) can take over an hour to reach optimum temperature. Moreover, many infrared saunas come in kit form and are easier to assemble, so they can be moved to a new location with relative ease, in contrast to the larger and more complicated hot rock saunas.
A central principle to the infrared sauna technology is emissivity. Emissivity is a dimensionless measurement of the relative ability of an object's surface to emit energy by radiation. Typically, the duller and darker an object, the greater its emissivity becomes. Emissivity can have a value from zero (0), as in the case of a shiny mirror that absorbs and radiates no energy, to 1.0, a theoretical maximum, described by a perfect “black body” in thermal equilibrium. The theory states a black body emits as much or more energy at every frequency than any other body at the same temperature. Real materials actually emit energy at a fraction of that of a black body; that is, real materials have emissivity values of less than 1.0. Some ceramics however, have exceptional emissivity values as high as 0.95.
Emissivity is further implicated by the way the human body radiates and absorbs heat energy, and thus IR/FIR energy. The average human body radiates and absorbs infrared energy through the skin at wavelengths of 3-50 μm with a concentration of that energy output at 9.4 μm. The goal of FIR heaters is to closely match the wavelength, and thus emissivity, thereby maximizing the rate at which the human body absorbs the IR/FIR energy, or heat. This results in more efficient, faster, and deeper absorption of radiated energy by the human body. In order to achieve this end, the heaters must be carefully designed to produce sufficient amounts of FIR energy within the appropriate band of wavelengths and frequencies.
Currently, the three (3) most common materials used in infrared heaters are ceramic, carbon, and infrared light-emitting diodes (LED). Ceramic is a very efficient and effective material when heated to produce infrared energy. Ceramic has a very high emissivity rating, thus it emits, or produces significant infrared heat. The drawback to ceramic heaters is that they tend to produce a shorter wavelength infrared energy than optimum for an FIR sauna application. This is troublesome because the human body does not as easily absorb shorter infrared wavelengths as it does longer FIR wavelengths. This renders sauna heaters that use only ceramic heating elements (and thus shorter wavelengths) less therapeutic.
In contrast, carbon infrared heaters produce a longer infrared wavelength. Carbon is very lightweight so the heaters can be bigger and can operate at a lower surface temperature. The lower surface temperatures of carbon heating elements produce longer wave infrared energy, resulting in radiated heat in the FIR spectrum. This heat is more readily absorbed by the human body and will produce results that are more desirable. The drawback of carbon heaters is that while they produce high quality FIR heat in the desired wavelength range, they do not commonly produce a significant amount of the energy, placing them lower on the emissivity curve than a ceramic heater alone.
The IR sauna market currently has a number of carbon-ceramic heaters available, however, the majority of these heaters emit the majority of their FIR energy between 0-7 μm, below the optimum, and 9.4 μm FIR energy the human body most efficiently absorbs.
Finally, LEDs provide still another option that has proven effective for IR energy production. While the wavelengths of IR energy emitted by IR LEDs are different from carbon and ceramic, their light weight and power output make them a viable alternative and useful as a heating FIR element. While an individual LED provides limited FIR output, many LEDs may be combined to form an array, creating a panel with similar characteristics to the carbon and ceramic panels discussed above. They may be further formed into smaller, portable or customizable sizes with the option of flexible mounting options for use in conjunction with, or independently from, the fixed carbon-ceramic heating elements.
Many people seeking the therapeutic benefits of infrared therapy can pay up to thousands of dollars per year for access to FIR saunas in health clubs, paying by session in spas around the country. The present invention will allow users to receive the benefit of both FIR sauna therapy and the LED therapy in the privacy of their own home.
The present invention incorporates multiple carbon and ceramic infrared panels mounted to or within the walls of the sauna cabin, in addition to one or more smaller IR LED arrays positioned to optimally transfer FIR energy to the individual sitting within the sauna. The walls and ceiling of the sauna cabin may all include such FIR-emitting panels.
A further limitation of typical saunas is interior space. Within the typical sauna, the interior is commonly outfitted with bench-style seating, allowing the user to comfortably enjoy the benefits of the sauna. The benches are most often constructed of wood, with wood slatted seats, allowing more air circulation between the seated user and the bench. Some larger saunas have multiple tiers of bench seating, allowing the user to take advantage of higher temperatures toward the ceiling and increasing available seating for multiple users. However smaller, personal saunas intended for home use are designed with efficient use of space as a primary concern, so as to minimize the sauna footprint, leaving minimal excess interior space. Moreover, while there is some flexibility in the user's physical position on the bench while seated, benches are fixed in place, restricting the user's seating options, further limiting floor space. This also leaves room for little more than simply sitting in place and sweating, as opposed to maximizing time spent with exercise or stretching.
Saunas have traditionally been used as a form of relaxation and detoxification. With the lower operating temperatures of an FIR sauna, users are now able to remain inside the sauna for up to or even exceeding one hour in duration. For most, this is a long period of time that might be used in more productive ways, such as an exercise routine. Initiating an exercise program inside a FIR heated sauna stimulates more intense workouts while stimulating even more sweat production. There is clinical evidence that conducting a resistance or anaerobic training session in such an environment is more effective for injury prevention, tissue repair, and recovery than the same workout in a normal gym environment.
Thus, by incorporating features into the construction of the FIR sauna cabin that allow the user to engage in physical exercise within the sauna cabin, a user benefits from the extended time spent in the sauna, in addition to the ability to use the time for other activities.
In light of the above, it would be advantageous to provide a far infrared heating element for IR saunas that produces the long wave infrared heat of carbon heaters combined with the very high infrared output of ceramic heaters, and the flexibility of LED-based infrared heaters. It would be further advantageous to provide a new technology that uses a combination of carbon, ceramic, and IR LEDs that can produce far infrared heat energy with a majority of that heat of a wavelength at or near the level of the human body's optimum absorption. It would further be advantageous to provide a sauna with user-configurable interior seating options and workout configurations allowing the user to exercise while simultaneously reaping the benefits of FIR therapy.